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Survey Methodology

Public-Use Data Files (Micro-data)

To NSAS 2006 Data Users:

The 2006 National Survey of Ambulatory Surgery (NSAS) public use data set was revised in April 2010 to correct an error in the calculation of the AGEINYRS variable for children under 1 year of age. The days and months of these children were incorrectly counted as years in the previously released public use NSAS file. This problem affected about 500 of the approximately 52,000 unweighted records in NSAS, and resulted in children under 1 year of age being misclassified into older age groups. This mistake was discovered when the age distribution obtained using the AGEINYRS variable was different from the one obtained using the AGER10 variable. We advise anyone who has used the AGEINYRS variable in analyses of NSAS 2006 data to rerun these analyses using the revised data set before reporting or publishing any 2006 NSAS data. The posted NSAS Documentation dated May 2009 is unchanged but the data user should note that the data set referred to as NSAS06REV0509.TXT in the documentation is now NSAS06REV0410.TXT. The NSAS06revreadme.txt document has been revised to include the new data set.

April 30, 2010

To NSAS 2006 Data Users:

The revised 2006 National Survey of Ambulatory Surgery (NSAS)
public use data set is now available for downloading from our website. The
revised public use file documentation
is also available. We advise anyone who has used the earlier NSAS data set (released in October 2008) to re-run all analyses using the revised data
set before reporting or publishing any 2006 NSAS data. The National Health Statistics Report Number 11, entitled "Ambulatory Surgery in the United States, 2006," [PDF - 468 KB]) has been revised and is now available. The reasons for the revision of the NSAS data set, which affected some of the procedure estimates, are discussed at the beginning of the public use file documentation and in the report. The report also explains that some other estimates of standard errors were printed incorrectly in the original report and these have been corrected. Estimates from the original report should not be used.